1. Field Of The Invention.
The present invention relates to retained earth structures in general and in particular to a retaining wall anchor system wherein tie rods or wire grid soil retention systems may be attached to retaining walls.
2. Description Of The Prior Art.
Retaining wall systems for soil retention have been in use for a great number of years increasing in complexity from simple beams, to concrete walls, wire mesh systems and prefabricated wall systems. Due to the forces of the earth pressing against the retaining walls, it is necessary to utilize anchoring systems to prevent overturning of the walls or other similar failures. Anchoring systems have evolved from simple bars bolted through the retaining walls to more complex wire mesh dead men interlocking with anchors embedded within the concrete retaining walls.
U.S. Pat. No. 569,995 issued to H. P. Boyd and U.S. Pat. No. 1,772,174 issued to F. E. Anderson are of interest as they disclose a means for making end to end connections of tie rods. These inventions utilize a threaded device which is expensive to manufacture and time consuming to install.
A number of patents disclose the use of threaded nuts and bolts to connect the tie rods to the retaining walls and frequently threaded nuts and bolts are used to connect the tie rods to dead men: specifically, the patents issued to Mason, U.S. Pat. No. Re.28,977; King, U.S. Pat. No. 2,902,743; Johnson, et al., U.S. Pat. No. 4,189,891; Hilfiker, U.S. Pat. No. 4,260,296; and Vilcinskas, U.S. Pat. No. 4,303,355. Bolted systems are expensive to make and are time consuming to install; they also require holes to be made through the wall and often through the dead men.
U.S. Pat. No. 2,152,816 discloses a fence in which bolts are similarly passed through the fence post and then the fence material is hooked to the ends of the bolts.
A patent issued to Hilfiker, et al., U.S. Pat. No. 4,329,089, and a patent issued to Broadbent, U.S. Pat. No. 4,470,728 both disclose a complex system in which anchors wrap around portions of the retaining wall and/or the retaining wall reinforcement steel. These anchors are then connected to the dead men systems by placing the end wires of the dead men over open hooks attached to the anchors or by bolting the rods to the anchors. These anchor systems are complex and expensive to install.
Three patents issued to Vidal, U.S. Pat. Nos. 3,686,873, 4,045,965 and 4,116,010 disclose anchors protruding from the retaining walls to which tie rods or anchoring straps are connected. In these patents, anchors are embedded within the walls or the wall panels and the tie rods are bolted to that portion of the anchors protruding from the wall. The use of bolts to make the tie rod connections is expensive and the installation is time consuming.
U.S. Pat. No. 4,449,857 issued to Davis discloses a system which includes a threaded anchor buried within a retaining wall and a threaded bolt which has been mounted on mesh soil reinforcement panels, a type of dead man. The threaded bolt must be screwed into the anchor to make the appropriate connection. This system is expensive to manufacture and time consuming to install.
U.S. Pat. No. 4,324,508 issued to Hilfiker, et al. discloses a U-shaped anchor embedded within a retaining wall in which the U-shaped portion extends exposed from the wall. The end wires of the soil reinforcement panels are passed through the anchors and are hand twisted or wrapped about the anchor to securely fasten the soil reinforced panels (dead men) to the retaining wall. The hand twisting is labor intensive.
U.S. Pat. No. 4,725,170 to Davis discloses a clevis member embedded into a wall panel having two welded loop ends protruding from the wall surface and a tie rod having a welded loop end which is placed between the clevis' looped ends. A bolt or rod is passed through all three loops to complete the connection. Such welded connections are expensive to manufacture.
It has been pointed out that the prior art is either so complex that it is expensive to make; requires threaded attachments which are expensive to make and time consuming to install or lastly, requires a considerable amount of welding which increases the costs of manufacture. Therefore, it remains clear that there is a need for a retaining wall anchor system that is simple to manufacture, easy to install and that does not require either welded or threaded connectors.